group concluded that the probability of an extraterrestrial anaerobic microorganism being able to contaminate a suitable environment on Earth is very low, but not zero.

For overall evaluation of returned samples warranting containment, it will be necessary to apply a comprehensive battery of tests combining both life-detection studies and biohazard screening. The task group concluded that detailed protocols and nondestructive methods still have to be developed to analyze samples, which are anticipated to be small in size but in great demand within the scientific community.


DeVincenzi, D.L. 1998. Workshop report on Mars sample return protocols. NASA Ames Research Center, Mountain View, Calif.

Egholm, M., A.O. Buchardt, L. Christensen, C. Behrens, S.M. Freier, D. Driver, R.H. Berg, S.K. Kim, B. Norden, and P.E. Nielsen. 1993. PNA hybridizes to complementary oligonucleotides obeying the Watson-Crick hydrogen-bonding rules. Nature 365:566-567.

Eschenmoser, A. 1997. Towards a chemical etiology of nucleic acid structure. Origins of Life and Evolution of the Biosphere 27:535-553.

National Research Council (NRC). 1997. Mars Sample Return: Issues and Recommendations. Washington, D.C.: National Academy Press.

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